No word in our language-not even "Socialism"-has been employed more loosely than "Mysticism." Sometimes it is used as an equivalent for symbolism or allegorism, sometimes for theosophy or occult science; and sometimes it merely suggests the mental state of a dreamer, or vague and fantastic opinions about God and the world. In Roman Catholic writers, "mystical phenomena" mean supernatural suspensions of physical law. Even those writers who have made a special study of the subject, show by their definitions of the word how uncertain is its connotation. It is therefore necessary that I should make clear at the outset what I understand by the term, and what aspects of religious life and thought I intend to deal with in these Lectures.